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In optics and photonics, circular polarizing films are key components used camera lenses to advanced display systems.
A circular polarizer film made by two layering materials: a Linear Polarizer Film and a quarter-wave plate. Linear polarizers work first, filtering incoming light so that it vibrates in one plane.
The function of a quarter wave plate is to produce a phase delay equivalent to one quarter of the wavelength of light. When linearly polarized light enters at a 45° angle to the fast axis, it splits into two beams (a fast beam and a slow beam). This linear polarization into circular polarization, the light's electric field rotates like a helix as it moves forward.
Circular polarization has a "handedness". If the electric field rotates clockwise as the light moves away, it is right-hand circular polarization. Counterclockwise? That's left-handed. This direction depends on the alignment of the quarter wave plate with respect to the incident light.
But linear polarizers are cheaper and still used in simple LCD screens or budget sunglasses.
Circular polarizer films are a quiet powerhouse in optics. By bending light’s behavior using birefringence and phase shifts.
Finally, circular polarizing films demonstrate how the weird properties of light, such as phase shift and birefringence, have created tools that shape modern technology.